Final answer:
The nurse should first assess the client's oxygen saturation levels using a pulse oximeter and check for any signs of respiratory distress or worsening COPD symptoms.
Step-by-step explanation:
The nurse should implement the following action first: assess the client's oxygen saturation levels using a pulse oximeter. This will help determine if the client's increased shortness of breath is due to decreased oxygen levels in the blood, which may require an adjustment in the oxygen therapy.
Additionally, the nurse should check the client's respiratory effort, auscultate lung sounds, and assess for any signs of respiratory distress or worsening COPD symptoms.
If the client's oxygen saturation is low or if there are other concerning findings during the assessment, the nurse should notify the healthcare provider for further evaluation and potential interventions.